Precisely controlled, contaminant free delivery of chemical products is vital in many manufacturing processes, and particularly in the manufacture of semiconductor products. For example, the high density, high performance requirements of current semiconductor products require ultra pure delivery of photoresist, free of external gasses, moisture and other contaminants. Consequently, problems experienced in the production of semiconductor products have demonstrated a need for improved chemical delivery systems to accommodate high yield production.
Unfortunately, prior art fluid delivery systems generally incorporate a large number of components which contribute to contamination of the delivered product. For example, present systems incorporate components, such as probes, filters, reservoirs, valves, transducers and fittings in line with the chemical fluids, each of which can serve as sources for gas and moisture contamination and, depending upon the nature of the dispensed materials and the cleaning procedures employed, may retain chemical deposits so as to subsequently become a source of particulate contamination which, in turn, results in a loss of product.
Additionally, structural alterations employed to minimize gas and moisture infusion, or to vent induced gasses, often result in system configurations which preclude full use of all the chemicals of a given batch. For example, venting of pressurized containers and elimination of reservoirs in many of the present systems inhibit the effective use of sensors for determining when the chemical batch is near substantial depletion. On the other hand, alternate methods for signaling near depletion, and thus the need for changeover to another batch, are relatively conservative, and consequently, waste material.